The invention relates to an electric motor and brake arrangement having a mechanical brake operating automatically in a rotary direction, which is to be used for example for driving household spin dryers, lawnmowers or similar devices.
For the stated purpose the use of so-called stop brakes is known, in which the brake force is brought about by means of springs. In the simplest manner, hand or foot levers serve to ease these braking devices, however these levers require additional expense on operation, and thus are not suitable for heavier loads. The sought after automatic easing of the braking device therefore takes place largely with the aid of lifting magnets which are energised at the same time as the motor winding and thus remove the brake from operation during acceleration of the electric motor. These lifting electro magnets however represent very expensive components, which moreover are susceptible to faults and cause humming noises, if the magnet surfaces in contact are corroded.
It has become known from German Patent Specification No. 751 092 to provide automatically operating mechanical brake, said brake being eased by partial rotation of the rotor arranged on a hollow shaft pivotably surrounding the output shaft against a spring force causing the brake torque. The construction chosen for this in the known electric motor is above all designed for the drive of lifting apparatus and as a result is equipped for reversible braking operation. Therefore, the known braking device involves a considerable constructional expense, which would give rise to excessively high costs in relatively simple devices for which the subject of application is to be suitable.